SAN DIEGO – More than 10% of geriatric patients presenting to emergency departments have signs of delirium, but not all delirium in the ED is equal, based on two presentations at the annual meeting of the Society for Academic Emergency Medicine.
For elderly patients in the emergency department, delirium is not merely present or absent. It is a heterogeneous syndrome, and certain subtypes likely indicate higher risk.
Dr. Jin Han
Dr. Jin Han, a researcher at Vanderbilt University in Nashville, Tenn., presented findings from a prospective, single-center observational study of 1,084 ED patients over age 65. Subjects were screened for delirium and their level of alertness. Of the 14% of patients with delirium, the researchers found the state of a patient’s arousal – decreased, normal, or increased – affected 6-month mortality.
In a separate study, Dr. Maura Kennedy of Harvard Medical School in Boston presented data suggesting that certain subtypes of delirium – particularly delirium with hypoactivity – are getting missed in the ED.
In Dr. Han’s study of 155 patients with delirium, a 4-point measurement called the Confusion Assessment Method for the Intensive Care Unit, (CAM-ICU) and the Richmond Agitation Sedation Scale (RASS) were used to measure delirium. Those with normal arousal as measured by RASS (n=15) had the highest 6-month mortality, at 40% (95% confidence interval, 20%-64%). In those with decreased arousal, the mortality rate was 27% (95% CI, 20%-35%); in those with increased arousal, mortality was 25%. The 6-month mortality rate in elderly ED patients without delirium was 11%.
Dr. Han acknowledged his study’s wide confidence intervals and the limitations of its single-site design and its screening tool, CAM-ICU, which has 70% sensitivity. Nonetheless, the findings imply that delirium needs to be looked at much more carefully in the ED. “Now if I see a patient with delirium and normal arousal, I want to make sure I rule out a potentially life-threatening illness,” he said in an interview.
Dr. Han’s research team is now collecting additional data, including etiology data and serum biomarkers, from ED patients with delirium in the hope of learning “why delirious patients with normal arousal do so poorly in terms of mortality.”
Dr. Maura Kennedy
Dr. Kennedy presented a study from a cohort of 622 ED patients age 65 and older, who were screened using a tool called the Memorial Delirium Assessment Scale. The researchers compared their screening results to what doctors and nurses observed in the ED. Dr. Kennedy and her colleagues found that physicians were more likely to document delirium in a nonhypoactive patient, compared with a patient with hypoactive delirium (78% vs. 45%; P = .02).
“After all, an 88-year-old person screaming or hallucinating will get your attention, while in a busy ED, someone sleeping quietly in a bed at 2 pm might not,” Dr. Kennedy said in an interview.
Hypoactive delirium is easy to miss and is associated with poor outcomes. It needs to be screened for in the ED, as it could be dangerous to discharge some patients with delirium. Even if the patient is admitted, she added, delirium “is not necessarily going to be picked up upstairs” in the hospital.
More research needs to focus on “trying to identify the underlying cause [of delirium] in patients presenting to the ED,” Dr. Kennedy said. “And we need to start really looking at delirium as indicative of something else being wrong.”
Dr. Han’s study was funded by the National Institute on Aging and by the Emergency Medicine Foundation Center; he disclosed a consulting relationship with Bio-Signal Group. Dr. Kennedy’s studies were funded by the National Institute on Aging, and the Dennis W. Jahnigen Career Development Award. She disclosed no conflicts of interest.